Nanoclusters of various inorganic layered compounds, like metal dichalcogenides--MX.sub.2 (M=Mo,W;X=S,Se), are known to be unstable in the planar form and to form a hollow cage--inorganic fullerene-like (IF--MX.sub.2) structures such as nested fillerenes and nanotubes (Tenne et al., 1992; Feldman et al., 1995 and 1996; published European Patent application No. EP 0580019) and structures with negative curvature (Schwartzites). Not surprisingly, nanoparticles of hexagonal boronitrides with graphite-like structure behaved similarly (Stephan et al., 1994; Chopra et al., 1995). Furthermore, nested fullerene-like polyhedra of MoS.sub.2 were synthesized at room temperature by a stimulus from an electron beam (Jose-Yacaman et al., 1996) in analogy to carbon-nested fullerenes (Ugarte, 1992), and also by application of an electric pulse from the tip of a scanning tunneling microscope (STM) (Homyonfer et al., 1996).
Intercalation of carbon nanotubes with alkali metal atoms from the vapor phase was recently described (Zhou et al., 1994). The intercalated films were found to arrange in stage-1 (n=1) superlattice, i.e. alkali-metal layers were stacked between each two carbon layers. The composite nanostructures were found to disintegrate when exposed to air, and complete shattering of the nanotubes (exfoliation) was obtained upon immersion in water. The intercalation of 2 H--MoS.sub.2 and 2 H--WS.sub.2 compounds was discussed in detail (Brec and Rouxel, 1986; Friend and Yoffe, 1987; Somoano et al., 1973), but staging was not observed in either of the former compounds, i.e. the alkali atoms were found to have a random distribution. Here too, deintercalation occurs upon exposure to air and exfoliation upon immersion in water.